JPH10326931A - Laser beam damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam damper which does not degrade over a long period of time, even for a laser beam of high output. SOLUTION: In this laser beam damper provided with a laser beam interrupt means 3 for interrupting the laser beam L outputted from a prescribed light source and an optical axis switching means 5 for guiding the laser beam L to the laser beam interruption means 3, the laser beam interrupt means 3 is constituted of plural laser beam branching means 7 for reflecting a part of the incident laser beam L into different directions and laser beam absorbing means 9 for absorbing the laser beam La which is reflected from the laser beam branching means 7, and the respective laser beam branching means 7 are arrayed along the optical axis of the incident laser beam L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam damper, and more particularly, to a laser beam damper capable of blocking high-power laser light.

[0002]

2. Description of the Related Art Laser processing using high-power laser light is widely used in the metal processing industry and the automobile industry. An apparatus for irradiating a laser beam is incorporated in a production line, and intensity control and ON / OFF control of the laser beam are performed according to a procedure programmed in advance.

Here, as a laser beam generally used for processing, there is a YAG laser or the like. This Y
A high-output solid-state laser represented by an AG laser has a feature that thermal stability leads to oscillation stability because a large part of input power changes into heat.

By the way, during oscillation of laser light,
Since the inside of the laser light source is cooled by circulating cooling water in order to suppress heat generation by the laser light, once the oscillation stops, the laser light source itself is rapidly cooled by the cooling water. When the laser oscillation is restarted, the laser light source itself may remain at a low temperature and may not be thermally stable. For this reason, there is a problem that a predetermined laser output cannot be obtained.

In order to solve this problem, when the interval between laser processings is short, the laser is kept oscillating, and a laser beam damper or the like for cutting off the laser light is provided outside the laser processing. A method is employed in which the laser beam is absorbed by a laser beam absorbing means in the laser beam damper. Further, when a laser beam is guided to a laser beam damper, a method is employed in which a predetermined reflection mirror is inserted into the optical axis of the laser beam to change the position of the optical axis and the like.

[0006]

However, in the above-mentioned conventional example, the following inconvenience has occurred.
That is, when high-power laser light is absorbed by a laser beam damper or the like, the problem is that the laser light absorbing means in the laser beam damper itself is processed by the high-power laser light, and the life of the laser beam damper is short. is there. In the case of a high-output YAG laser that performs pulse oscillation, the laser output has a high peak intensity, and thus tends to be particularly problematic.

When a reflecting mirror for guiding the laser beam to the laser beam absorbing means of the laser beam damper is inserted into the laser beam path while the laser beam is oscillating, the reflecting mirror itself becomes a high-power laser from the peripheral region. There has been a problem that it is easily processed by light. In this case, there is a case where the laser oscillation is temporarily stopped when the reflection mirror is inserted into the optical path, and the laser is oscillated again after the insertion of the reflection mirror. However, as described above, once the oscillation is stopped, the laser light source itself is cooled, thereby causing a disadvantage that the stability of the laser light is impaired.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the disadvantages of the prior art, and to provide a laser beam damper which does not deteriorate for a long period of time even with high-power laser light.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a laser light blocking means for blocking laser light output from a predetermined light source, In a laser beam damper provided with an optical axis switching means for guiding laser light, the laser light blocking means,
A plurality of laser light branching means for reflecting a part of the incident laser light in different directions, and a laser light absorbing means for absorbing the laser light reflected from the laser light branching means, each laser light branching means, The arrangement is such that the laser light is arranged along the optical axis of the incident laser light.

With the above configuration, the laser light emitted from the light source is made incident on the laser light blocking means by the optical axis switching means. The laser light incident on the laser light blocking means passes through the laser light branching means. At this time,
In each laser beam branching unit, a part of the laser beam is branched toward the laser beam absorbing unit, and a part is transmitted as it is. The laser light branched by each laser light branching means is absorbed by the laser light absorbing means. Since the laser light branched to the laser light absorbing means by each laser light branching means has a low intensity, the laser light absorbing means is not processed by the laser light.

Further, the invention according to claim 2 employs a means in which the laser beam branching means is constituted by a transparent substrate having a predetermined refractive index, and the other structure is the same as the invention according to claim 1.

According to a third aspect of the present invention, in the laser beam branching means made of a transparent substrate, the surface of the transparent substrate on the downstream side of the laser beam is coated with a dielectric multilayer film. This is the same as the invention described in Item 2.

According to a fourth aspect of the present invention, a predetermined light detecting means is provided on the optical axis of the laser light and at the most downstream side of the laser light branching means. This is the same as the invention described in 2 or 3.

Further, according to the fifth aspect of the invention, the optical axis switching means is constituted by a predetermined reflecting mirror, and the optical axis switching means is constituted so as to be movable along the optical axis direction of the laser light from the light source. The other configuration is the same as that of the first, second, third, or fourth aspect of the present invention.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Here, FIG. 1 is a configuration diagram of the laser beam damper 1 according to the present embodiment. The laser beam damper 1 includes a laser light blocking unit 3 that blocks a laser beam L output from a predetermined light source (not shown), and an optical axis switching unit 5 that guides the laser beam L to the laser beam blocking unit 3. Have. The laser light blocking means 3 includes a plurality of laser light branching means 7 for reflecting a part of the incident laser light L in different directions, and a laser light absorbing means for absorbing the laser light L reflected from the laser light branching means 7. The laser beam branching means 7 is arranged along the optical axis of the incident laser light L.

More specifically, the laser light L is emitted from a predetermined light source (not shown), and is, for example, a YAG laser. The YAG laser is radiated in a pulse shape, and has a peak output higher than that of the laser light continuously radiated. Therefore, it is widely used for processing. However, the laser beam damper 1 of the present invention is not limited to a YAG laser.
It can be applied to all types of laser light.

A predetermined optical axis switching means 5 is provided downstream of the laser beam L emitted from the light source. The optical axis switching means 5 is constituted by a reflection mirror, and has a role to bend the optical path of the irradiated laser light L at a right angle. For this reason, it is inclined at an angle of about 45 degrees with respect to the light source side. The optical axis switching means 5 moves in parallel along the optical path of the laser light L from the light source. Due to the parallel movement of the optical axis switching means 5, the optical axis position of the laser light L also moves in parallel.

The laser light L after being bent is incident on a laser light blocking means 3 to be described later. In the laser light blocking means 3, transparent substrates 7a, 7b,... As laser light branching means 7 are arranged in a line along the optical axis of the incident laser light L. Each laser beam branching means 7 is inclined at approximately 45 degrees with respect to the upstream side of the laser beam L, and bends a part of the incident laser beam L at a right angle. The transparent substrates 7a, 7b... Are made of a material having excellent heat resistance and light resistance. In this embodiment, quartz glass is used. When the laser light L passes through each of the transparent substrates 7a, 7b,..., The intensity level of the transmitted laser light L is attenuated by about 8% due to the refractive index of the quartz glass. The laser beam L corresponding to this attenuation is branched in different directions.

In this embodiment, a part of the laser beam L is bent vertically downward by the laser beam branching means 7a, 7b. The laser light blocking means 3 of the present embodiment includes six laser light branching means 7. However, this is only an example, and may be more or less than six.

The laser light L branched by the laser light branching means 7 is applied to the laser light absorbing means 9 provided in the branching direction.
Is absorbed by The laser light absorbing means 9 may be made of any material having good thermal conductivity and easily absorbing laser light. In the present embodiment, copper is used. Cooling water is circulated inside the laser light absorbing means 9 to release the heat generated by the irradiation of the laser light L and cool the laser light absorbing means 9.

The function of the laser beam damper 1 configured as described above will be described with reference to FIG. 1. The laser beam L emitted from the laser light source is bent by the reflection mirror as the optical axis switching means 5 in the optical path. Is done. Then, the bent laser light L is guided into the laser light blocking means 3. At this time, when the optical axis switching means 5 is at the position A in the figure, the laser light L is not attenuated at all and passes through the laser light blocking means 3 as it is. Then, the laser beam is irradiated to a processing optical system on the downstream side, and predetermined laser processing is performed.

On the other hand, when cutting off the laser light L, the optical axis switching means 5 moves in parallel (downward in the figure) along the optical path of the laser light L from the light source. Then, the optical axis switching means 5 is positioned at the position B in the figure. As a result, the optical axis of the laser beam L after being bent also moves in parallel with the movement of the optical axis switching means 5. Then, the optical axis of the switched laser light L is the position of the laser light branching means 7.

First, the laser beam L bent by the optical axis switching means is supplied to the closest laser light branching means 7a.
Is incident on. In the laser beam branching means 7a on the most upstream side, a part of the laser light La is branched toward the laser light absorbing means 9 (downward in the drawing), and the remaining laser light L is transmitted as it is. At this time, the intensity of the laser light L transmitted through the laser light branching means 7 is reduced by about 8%. Further, since the laser beam branching means 7 itself is formed of a transparent substrate made of quartz glass, even if the laser beam L is incident, it is not processed by the laser beam L.

The laser beam L transmitted through the laser beam branching means 7a on the most upstream side enters the next laser beam branching means 7b. Also in the laser beam branching means 7b, a part of the laser light L is branched toward the laser light absorbing means 9 as in the case described above, and the rest is left as it is.
Through. At this time, the intensity level of the transmitted laser light L is also attenuated by about 8% as compared with before the incident. As described above, the laser beam L is supplied to each laser beam branching unit 7.
While passing through a, 7b,..., the intensity level gradually decreases. Assuming that the laser beam splitting means 7a, 7b.
If the intensity of the laser light L is equally attenuated by about 8%, the light can be transmitted through about 20 laser light branching means.
The final intensity of the laser light L can be reduced to about 20% of the initial intensity.

On the other hand, the laser beam La incident on the laser beam absorbing means 9 is supplied to the laser beam branching means 7a located at the uppermost stream.
Is about 8% of the intensity of the original laser beam L. Therefore, the laser light absorbing means 9 is not easily processed by the laser light La. Then, a total reflection mirror 11 for completely reflecting the laser light L is provided at the most downstream of the laser light branching means 7, and all the laser light L is absorbed by the laser light absorbing means 9 so that the laser light L is completely absorbed. Can be shut off.

The laser beam absorbing means 9 supplies the laser beam La
Is absorbed, the laser light absorbing means 9 is heated according to the intensity of the laser light La. In this case, the laser light absorbing means 9 is constantly cooled by the cooling water circulating inside. For this reason, the temperature does not rise so as to adversely affect the laser light absorbing means 9.

In the laser light blocking means 1 of the present invention, even when the laser light L is constantly irradiated, the reflecting mirror as the optical axis switching means 5 moves along the optical path of the laser light L, so that it is processed. The laser beam L whose edge part is easy to have high intensity
And damage to the laser beam L is greatly reduced. The intensity of the laser beam La branched by the quartz glass laser beam branching means 7 and reaching the laser beam absorbing means 9 is determined by the laser beam branching means 7a and 7b.
b is about 8% of the laser light L transmitted therethrough, so that the degree of processing of the laser light absorbing means 9 itself is greatly reduced.

As described above, in the laser light blocking means 1 of this embodiment, all the laser light branching means 7 use a transparent substrate of quartz glass. However, the present invention is not limited to this. That is, the laser light L
The above-mentioned transparent substrate is disposed on the upstream side, and a laser beam branching means disposed on the downstream side where the intensity of the laser light L is attenuated to some extent is a laser beam branching means coated with a dielectric multilayer film. You may. This is because if the intensity of the laser beam is reduced, even if a laser beam branching unit having a large light absorption is used, the laser beam is not easily processed. As described above, when a part coated with a dielectric multilayer film is used as a part of the laser beam branching unit, the number of laser beam branching units can be reduced. Here, zircon dioxide or the like is used as the material of the dielectric multilayer film.

Next, a second embodiment of the present invention will be described with reference to FIG. The embodiment is the first embodiment described above.
This embodiment has the same main components as those of the first embodiment. The difference from the first embodiment is that instead of using the total reflection mirror 11 provided on the most downstream side of the laser light branching means 7, a light detecting means 13 for detecting the intensity of the transmitted laser light L is provided. That is.

In processing with the laser light L, it is necessary to detect the intensity of the laser light L in order to maintain processing accuracy and quality. However, if the laser light L with high intensity is directly incident on the light detecting means 13, the laser light L greatly deteriorates the light receiving surface and has a problem that it cannot be used for a long time. For this reason, as in the present embodiment, the laser light is passed through the laser beam branching means 7 for which the overall attenuation rate is calculated in advance, and
The method of measuring the laser light L whose intensity has decreased to such a degree that the light receiving surface of 3 is not easily deteriorated and deriving the intensity of the original laser light L from the attenuation factor is practical for a laser processing system introduced into a production line. It is.

[0031]

The present invention is constructed and functions as described above,
In particular, according to the first aspect of the present invention, the laser light blocking means includes a plurality of laser light branching means for reflecting a part of the incident laser light in different directions, and absorbs the laser light reflected from the laser light branching means. The laser beam splitting means is arranged along the optical axis of the incident laser light. Therefore, the laser irradiation on the workpiece is turned ON / OFF while the high-output laser light is oscillating.
In addition, the deterioration of each component disposed in the laser beam blocking means is suppressed, and an excellent effect of enduring long-term use is produced.

According to the second aspect of the present invention, the laser beam branching means is constituted by a transparent substrate having a predetermined refractive index. For this reason, the laser beam branching unit has an excellent effect that it is difficult to absorb the laser beam, and the laser beam branching unit itself is not processed by the laser beam.

According to the third aspect of the present invention, the surface of the transparent substrate on the downstream side of the laser beam among the laser beam branching means comprising the transparent substrate is coated with a dielectric multilayer film. For this reason, compared with the case of using the laser beam branching unit made of the transparent substrate, an excellent effect that the laser beam can be cut off by a smaller number of laser beam branching units is produced.

According to the fourth aspect of the present invention, the predetermined light detecting means is provided on the optical axis of the laser light and at the most downstream side of the laser light branching means. For this reason, if the attenuation rate in the laser beam branching means is calculated in advance, it is possible to derive the initial laser light intensity by detecting the intensity of the laser light after the intensity is reduced by the light detecting means. Effect.

Further, according to the fifth aspect of the present invention, the optical axis switching means is constituted by a predetermined reflection mirror, and the optical axis switching means is movable along the optical axis direction of the laser light from the light source. Configured. For this reason, since the optical axis switching means itself does not expose the edge portion to high-intensity laser light, the edge portion is not processed and has an excellent effect of being able to withstand long-term use. Occurs.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser beam damper 3 laser light blocking means 5 optical axis switching means 7, 7a, 7b laser light branching means 9 laser light absorbing means 13 light detection means

Claims (5)

[Claims] 1. A laser beam damper comprising: a laser beam cutoff unit for blocking a laser beam output from a predetermined light source; and an optical axis switching unit for guiding the laser beam to the laser beam cutoff unit. The blocking means comprises a plurality of laser light branching means for reflecting a part of the incident laser light in different directions, and a laser light absorbing means for absorbing the laser light reflected from the laser light branching means; A laser beam damper, wherein the light splitting means is arranged along the optical axis of the incident laser light. 2. The laser beam damper according to claim 1, wherein said laser beam branching means is constituted by a transparent substrate having a predetermined refractive index. 3. The laser beam damper according to claim 2, wherein, of the laser beam branching means made of the transparent substrate, a surface of the transparent substrate downstream of the laser beam is coated with a dielectric multilayer film. 4. A laser beam according to claim 1, wherein a predetermined light detecting means is provided on an optical axis of said laser light and at a most downstream side of said laser light branching means. damper. 5. The optical axis switching means is constituted by a predetermined reflection mirror, and the optical axis switching means is configured to be movable along the optical axis direction of the laser light from the light source. Item 4. A laser beam damper according to Item 1, 2, 3, or 4.